catalog-backend-module-okta: update config to include a schedule object

[GoFightNguyen]

There are two confusing aspects of the config for catalog-backend-module-okta

1. The config.d.ts does not match the expectation of catalog.providers.okta being a configArray, see here

2. A schedule is expected to be defined like catalog.providers.okta[0].frequency (see code) rather than as a schedule object like catalog.providers.okta[0].schedule. The latter seems to be the common approach in backstage, see this example.

Feature Suggestion

Specify the expectation of a schedule in the config.d.ts and support the frequently used approach of a schedule object.

Context

@roadiehq/catalog-backend-module-okta v0.10.2, using the new-backend-system as per the docs.